I have done this conversion many times. There are 2 bolts on the firewall in what looks like the correct place (one above the other) . Use the bottom bolt as the top hole of the cyl.I have always used just a cheap PBR trailer type cyl (5/8 depending on slave cyl size). Push rod length may have to be lengthened. Screw a rosejoint to the pushrod.rosejoint will be about 12mm to the pass side of the standard corolla pedal. Drill a whole in the pedal and fit a 12 mm ( or whatever is required to line it up) spacer between pedal and rosejoint. Fit a bolt through the whole lot and you are done.
Any questions just ask.